Gas generants are employed as a means for producing a source of power for performing a variety of functions. An important function in liquid rocket systems or hybrid rocket sytems is the pressurizing or expelling of liquids from tanks. The well known reactive oxidizer, IRFNA (inhibited red fuming nitric acid) has been employed with the liquid fuel UDMH (unsymetrical dimethylhydrazine) in a liquid rocket system. The IRFNA is expelled from a storage tank in a controlled ratio with the fuel UDMH at a controlled ratio to produce a hypergolic reaction which provides propulsion gases for propelling a rocket that is fitted with an exhaust nozzle and the other necessary fixtures and controls.
The prior art has employed nitrogen gas as the pressurizing media; however, this requires maintaining a pressurized system or a liquid nitrogen system which adds complexity as well as increased weight as a result of required storage tanks and equipment to utilize this type pressurizing media.
If the pressurizing media is reactive with the liquid being expelled then a piston system or a diaphragm arrangement to provide the necessary separation between the media and liquid is required. A failure of either the piston or diaphragm could cause failure of the system from subsequent reactions resulting from contact of the media with the liquid.
A self-generating gas-pressurization system which employs sodium azide as the gas source has been utilized with some degree of success. An undesirable feature of the sodium azide as a gas generant is the high percentage of byproducts which results. The byproducts include about 35% metallic sodium and sodium salts which require separation. Separation can be effected through their injection through a swirltype injector into a cycloidal hollow chamber. The heavy constituents of the decomposition products are thrown outward by centrifugal action. Starting of the decomposition of the sodium azide is done by means of a slug of IRFNA.
The pressurizing media is required to be non-reactive with the IRFNA if there is likelihood of contact between it and the IRFNA. Thus, the requirement for separation of the solid media from the azide reaction, which would interfere with the normal functioning of the pressurizing system, increases complexity.
Desirable is a self-generating gas pressurizing system which produces a neutral gas or a non-reactive gas which, if brought into contact with IRFNA, would not interfere with normal functioning of the oxidizer or fuel.
Therefore, an object of this invention is to provide a high nitrogen-containing compound for use as a gas generant.
Another object of this invention is to provide a method of producing near-neutral combustion products, substantially free of particulate matter, which serve as the expulsion media for a reactive oxidizer, such as, IRFNA, from its storage tank.
A further object of this invention is to provide a method of producing near-neutral combustion products which can be employed without further treatment in a control system for thrust vector purposes.